The present invention pertains to a processing station on motor vehicle assembly lines, with a mounting means for a motor vehicle part or for a transport means intended therefor, which is rotatable around a horizontal axis of rotation, with conveyors, which end in front of and behind the processing station, and with another conveyor, which is arranged between the conveyors and can be raised and lowered.
Such processing stations, which are also called lifting and rotation units, can be placed in various areas of a production line in order to assemble or process motor vehicle parts, especially body parts. This may be carried out manually or in automated operation. The drives for the height adjustment and for the rotation or pivoting of the mounting frames are equipped for this purpose with control and positioning means in order for the motor vehicle part braced on the mounting frame to be able to be brought into a desired position for the processing. The conveyors ending in front of and behind the processing station are arranged for loading in the longitudinal direction, i.e., in the direction of the axis of rotation of the mounting means.
In a prior-art processing station of the type described in the introduction (DE 4437901 A1, embodiment corresponding to FIG. 14), the mounting means has a single mounting frame, which comprises two mounting arms and which is fastened either cantilevered at one end of the processing station on a rim bearing or at both ends on a rim bearing each. The motor vehicle part located on a transport means is transported in this embodiment by the conveyors ending in front of the processing station onto the additional raised conveyor located within the processing station. The additional conveyor is then lowered until the motor vehicle part lies on the mounting frame outside the transport means. The motor vehicle part subsequently must be locked with the mounting frame and separated from the transport means so that the additional conveyor with the transport means locked thereon can be lowered further. The separation of the motor vehicle part from the transport means prior to the processing and the subsequent relocking represent additional operations. Moreover, there is no flexibility in terms of the level at which the processing is carried out because of the fixed arrangement of the horizontal axis of rotation of the mounting frame. The mounting arms of the mounting frame, which extend in the longitudinal direction, additionally compromise the free accessibility from the side. Finally, the manufacturing effort and the cost of acquisition for the rim bearing or the rim bearings are very substantial.
In another processing station (EP 0432673 A1), each mounting frame is held on one column only, which is located centrally in front of the mounting frame and therefore hinders or prevents the loading of the processing station with a motor vehicle part or a transport means (transport skid) for the motor vehicle part. Therefore, the motor vehicle part can be introduced between the columns and placed on the mounting frame and braced therewith from the side only.
In another embodiment (DE 44 04 422), a continuous rotor with a plurality of mounts arranged on the circumference on the rotor for the motor vehicle part or for a transport skid extends between the columns arranged centrally. Even though the motor vehicle parts or the transport skid can thus be brought to the mounts in the direction of the axis of rotation of the rotor and braced therewith, the rotor with the mounts is not adjustable in height and, in addition, the design of the rotor hinders the manual or automatic processing of the motor vehicle part.
Finally, a repair workshop for railroad cars, especially railroad freight cars, with a processing station has been known from U.S. Pat. No. 4,295,427. A track, on which the railroad cars move into the processing station and leave same, with new or repaired bogies, extends through the entire workshop. The processing station has at one end a longitudinally displaceable portal with a crosshead which is synchronously adjustable in height and with a mounting arm, which is arranged rotatably thereon and which is provided with a coupling element and two tension chains, with which the car body can be grasped and lifted off from the bogies, rotated around its longitudinal axis and deposited again, optionally on other bogies. The workshop is neither suitable nor intended for the transport of a motor vehicle part located on a transport means, especially a transport skid, into the processing station.
The object of the present invention is to provide a processing station, which is freely accessible and loadable from all sides.
This object is accomplished by the mounting means or mechanism comprising two mounting frames arranged at mutually spaced locations from one another, which are arranged on a crosshead each and are synchronously rotatable around the horizontal axis of rotation. Each crosshead is mounted and guided on two columns arranged on both sides of the axis of rotation and both crossheads are synchronously adjustable in height. The conveyors end in front of the crossheads above the lowered crossheads and the lowered mounting frames. The mutual distance between these columns is greater than the width of the motor vehicle part or of a transport means for the motor vehicle part. On the whole, the processing station consequently has four columns, which are arranged in the area of a rectangle formed by them, so that motor vehicle parts or transport skids intended for them can be introduced into the processing station from all sides. Since the motor vehicle parts or the transport skids are braced with the mounting frames at their respective ends only, all areas of the motor vehicle part located in the processing station are freely accessible for manual as well as automatic processing in case of a corresponding height adjustment and rotation of the mounting frames.
One of the columns of each crosshead for the mounting frames is preferably designed as a drive column and the other column as a guide column. Each mounting frame is preferably arranged rotatably on a crosshead, which is mounted and guided on the two columns.
For loading in the longitudinal direction, i.e., in the direction of the axes of rotation of the mounting frames, conveyor belts may be arranged, which end in front of the crossheads. In addition, an additional conveyor is arranged, which is arranged between the two crossheads and can be raised and lowered. The conveyors preferably end in front of the crossheads above the lowered crossheads or the lowered mounting frames. The conveyor, which can be raised and lowered, needs to extend only between the ends of the mounting frames. In another embodiment, the conveyor, which can be raised and lowered, may extend into the area of the mounting frames and have end-side openings for the passage of the mounting frames during a relative movement between the mounting frame and the conveyor. All conveyors are preferably designed as roller conveyors.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For abetter understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.